 /*******************************************************************************
  * Copyright (c) 2004, 2006 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.ui.internal.dnd;

 import org.eclipse.jface.util.Geometry;
 import org.eclipse.swt.SWT;
 import org.eclipse.swt.graphics.Point;
 import org.eclipse.swt.graphics.Rectangle;
 import org.eclipse.swt.widgets.Control;

 /**
  * Compatibility layer for the old-style drag-and-drop. Adapts an old-style
  * IPartDropListener into an IDragTarget.
  *
  */
 public class CompatibilityDragTarget {

     // Define width of part's "hot" border
 private final static int MARGIN = 30;

     /**
      * Returns the relative position of the given point (in display coordinates)
      * with respect to the given control. Returns one of SWT.LEFT, SWT.RIGHT, SWT.CENTER, SWT.TOP,
      * or SWT.BOTTOM if the point is on the control or SWT.DEFAULT if the point is not on the control.
      *
      * @param control control to perform hit detection on
      * @param toTest point to test, in display coordinates
      * @return
      */
     public static int getRelativePosition(Control c, Point toTest) {
         Point p = c.toControl(toTest);
         Point e = c.getSize();

         if (p.x > e.x || p.y > e.y || p.x < 0 || p.y < 0) {
             return SWT.DEFAULT;
         }

         // first determine whether mouse position is in center of part
 int hmargin = Math.min(e.x / 3, MARGIN);
         int vmargin = Math.min(e.y / 3, MARGIN);

         Rectangle inner = new Rectangle(hmargin, vmargin, e.x - (hmargin * 2),
                 e.y - (vmargin * 2));
         if (inner.contains(p)) {
             return SWT.CENTER;
         } else {
             return Geometry.getClosestSide(inner, p);
         }
     }

 }

